Planar inverted F antennas generally include at least one planar radiating element and a ground plane in a plane parallel to the radiating element. A short tab at one end of the radiating element that extends transverse to the radiating element is connected to the ground plane. A coaxial cable extends through the ground plane at a selected location and the center pin of the coaxial cable is connected to the radiating element. This type of antenna is called an inverted F antenna because the side profile is shaped like the letter F with the radiating element forming the long portion, the tab forming top transverse leg and the center pin of the coaxial cable forming the other transverse leg. In prior known planar inverted F antennas, the radiating element is located relatively near the ground plane so that the length of the tab is less than 10% of the length of the radiating element.
Planar inverted F antennas are used in wireless communications. As the number of wireless applications increases and the physical size of wireless devices decreases, antennas for these applications and devices are needed. Prior known planar inverted F antennas have been limited by the required size of the radiating element, the required size of the ground plane, limited bandwidth and limited isotropic characteristics.